What IS IT ?

noexec is a package for preventing process(es) from executing exec system call.
Primary intent was use noexec with sudo. But sudo from version 1.6.7.p5
implement noexec functionality itself. So, if you still interesting...

Supported platforms.

noexec was tested on:

Linux x86

Linux alpha

Linux sparc

SunOs 5.8 sparc

FreeBSD 4.9 x86

NetBSD 1.6.1 x86

And it should be ease portable to any Unix with LD_PRELOAD supported.

WHERE IT CAN BE USEFULL ?

Provide user with some kind of menu and prevent him from escape to the shell

sudo configuration - you can be sure user will not got a shell

may be for preventing some kinds of exploits of CGI scripts

HOW USE IT ?

LD_PRELOAD=/usr/lib/libnoexec.so vi # vi will be unable to run any shell command

In the /etc/sudoers:
user ALL = /usr/bin/noexec /usr/bin/less /etc/shadow